Converted by
Mathematica
June 17, 2001
![[Graphics:../Images/Pratica7_gr_48.gif]](../Images/Pratica7_gr_48.gif)
![[Graphics:../Images/Pratica7_gr_49.gif]](../Images/Pratica7_gr_49.gif)
![[Graphics:../Images/Pratica7_gr_50.gif]](../Images/Pratica7_gr_50.gif)